Behind the headlines -- the news of last month's gross national products, the endless debates about industrial policy and protective tariffs, the stories of the latest hostile takeover -- is a world of economic growth that is almost invisible. The businsspeople who inhabit this world don't make the papers, and they don't make waves on Wall Street. Their companies are mostly young, and are still privately held. It isn't exactly a world of small business -- not as the term is usually understood -- but it isn't big business, either. Nor is it simply a world of high technology. About all the companies have in common is that they are growing so fast they won't be invisible for long. They are temorrow's news.

Every year, INC. ranks the standouts of this world: the 500 fastest-growing private companies in America. If you think you must already know these companies, glance through the list. Maybe you recognize Herbalife International, the direct-sales company that is the list's top gainer, if only because of its notoriety (see "Unbridled Growth," page 100). And maybe you know another name or two. But the chances are good that you haven't heard of, say, SpeeDee Oil Change & Tune-Up (#84), founded in 1980 by Gary Copp in Kenner, La. SpeeDee, which advertises that it will change your oil in 9 minutes and tune your car's engine in 30, went from about $110,000 in sales five years ago to nearly $2.5 million last year, and increased its work force almost 10 times. That's growth. But outside of Kenner, it made no headlines.

As a group, the companies on the INC. 500 challenge the stereotypes about the origins of our economic growth. Look, for example, at the number of computer-related businesses on the list. The recent shakeout in the industry doesn't show up on a list that tracks five-year growth, and in fact, some 105 companies (21% of the total) are manufacturers or distributors of computer hardware, software, or systems. But that leaves nearly 400 companies that have little or nothing to do with computers; indeed, most of these 400 aren't high-technology enterprises of any sort. CTEC Inc. (#476) is a manufacturer of ski chair lifts. International Medical Centers Inc. (#40) is a health maintenance organization. Hinkle Metals & Supply Co. (#483) is a distributor of roofing and sheet metal. There are, on the list, 11 publishers, 17 consulting firms, 27 contractors and builders, and an operator of hair and tanning salons.

Service industries are supposed to be the fastest-growing sector of the U.S. economy, and the list supports this belief -- up to a point. More than 40% of the companies on this year's INC. 500 perform some kind of service, ranging from American Trans Air Inc. (#7), a 12-year-old airline based in Indianapolis, to Phoenix Advertising, Design, & Promotion Inc. (#500), which, despite its name, makes its home in Elm Grove, Wis. Another 25% of the companies, however, are in wholesale or retail distribution, and 26% are engaged in what is supposed to be yesterday's business, manufacturing. INC. 500 companies -- and these are companies, remember, that have grown at a minimum of 464% over five years -- manufacture floor-cleaning equipment, carbon paper, computer keyboards, hearing aids, waterbeds, fiberglass moldings, and magnetometers. Fayette Manufacturing Corp. (#5) makes windmills and other wind-energy equipment. Weathervane Window Co. (#201) makes wooden windows.

INC. 500 companies reside in 43 states and the District of Columbia. There are, as might be expected, plenty of companies from New England (33); from New York, New Jersey, and Pennsylvania (65); and from Texas (35). And yes, California is far and away the single-state leader, with 101 representatives. But consider the distribution of the remaining 266 companies. Seventy-four of them make their home in a pure Rustbelt region that includes Ohio, Michigan, Illinois, Indiana, and Wisconsin. Eighty-seven are in the southeastern coastal states, Virginia through Florida. The rest are pretty well scattered. Delaware, Kentucky, Louisiana, Nebraska, New Mexico, South Dakota, Utah, Vermont, and Wyoming registered one company each, and the only states that didn't make the list were Maine, Mississippi, Montana, Nevada, North Dakota, Oklahoma, and West Virginia. Alaska and Hawaii counted 3 companies apiece.

The most important measure of economic growth may be the creation of jobs. This is an area in which the U.S. economy, despite its sometimes sluggish performance, has outshone the rest of the world in recent years. American employers created some 24 million jobs from 1974 to 1984, outstripping not only Western European countries (which were actually losing jobs), but also Japan (which was generating them much more slowly).

Many of these jobs came from the growth of small, private companies like those on the INC. 500. Five years ago, the companies on this year's list employed a total of roughly 12,600 people. In 1984, they employed nearly 63,600, an overall increase of more than fivefold. The average company in this period added 100 new workers. To be sure, not all the jobs were new positions. Employment leader Pedus International Inc., for example (Pedus was last year's #1 company and ranks #101 this year), added 5,600 employees over five years, thanks in part to its five acquisitions. National Health Care Affiliates Inc. (#23) added 1,517 new employees, partly through its 14 acquisitions. But Hall Financial Group (#208) increased its work force from 835 to 2,150 with only a single acquisition (which accounted for only 19 workers); and Solectron Corp. (#144), an electronics manufacturer, went from 150 employees to more than 2,000 with no acquisitions at all. Overall, four out of five companies on the list grew without acquiring any other company.

Job creation and productivity are often opposite sides of the same coin. Capital equipment that allows a company to maintain output while cutting its work force may lead to a loss of jobs even while it boosts productivity. Critics charge, moreover, that America's job-generation record has merely reflected the replacement of high-productivity, high-wage jobs by low-productivity, low-wage jobs.